More specifically, an opening rim has been designed in the invention especially intended for metal containers having the shape of a cylinder of revolution intended to contain paints, enamels and other liquid products which require a hermetic seal for their preservation.
The present rim has special features which render it advantageous in practice with respect to the embodiments currently known on the market and which are intended for similar uses, by incorporating the precise conditions by means of which it is possible to reduce its cost since its manufacture is totally mechanical, achieved by means of one single operation of folding the rim of the opening of the container in order to obtain two concentric and substantially staggered flanges, all from one single sheet of metal, contrary to the traditional system which required a complex and expensive process to achieve an identical result.
In fact, the presently known technique requires first the making of the flange of the container in order to obtain a substantial widening of its opening; the manufacture of a metal ring with a particular section; and, finally, the joining of both elements by means of a mechanical process.
From the above, the considerable increase in cost represented by a traditional opening rim with respect to the opening rim which is the subject of the present registration is obvious, the latter being obtained by means of a single operation, the result of which is an opening rim of optimum type for receiving the lid which forms the hermetic seal.